Mattis: War with North Korea would be 'catastrophic'

"My portfolio, my mission, my responsibility is to have military options if you need it", Mattis responded.

Speaking to reporters in Mountain View, California, Mattis said that USA efforts on North Korea were now focused on diplomacy, while stressing that his "mission" was to make sure Washington "is to have military options should they be needed".

"The American effort is diplomatically led, it has diplomatic traction, it is gaining diplomatic results and I want to stay right there right now", he added. "But at the same time, our defenses are robust".

North Korea said on Wednesday it was considering a missile attack on the USA island of Guam, which hosts several United States military bases.

Mattis became the latest senior member of the Trump administration to issue dire warnings to North Korean leader Kim Jong Un, declaring Wednesday that Pyongyang "should cease any consideration of actions that would lead to the end of its regime and the destruction of its people".

"[Kim Jong-un] has been very threatening beyond a normal statement, and as I said, they will be met with fire, fury, and, frankly, power, the likes of which this world has never seen before", Trump concluded.

Mattis' comments come on the heels of North Korea's state media announcement Thursday that its military would devise a plan by mid-August to fire four intermediate range missiles at the USA territory of Guam as a "crucial warning to the U.S". "This is my rhetoric".

Nonetheless, a war of words is being waged between President Donald Trump and Pyongyang.On Aug. 11, Trump affirmed via Twitter that the U.S.is "locked and loaded" for action against North Korea if provoked, saying "military solutions are now fully in place".